Annelations with Tetrachlorothiophene 1,1-Dioxide

Article abstract of DOI:10.1021/jo01293a019

Tetrachlorothiophene 1,1-dioxide is a reactive, cheletropic Diels-Alder reagent.It has been used to annelate, with loss of sulfur dioxide, a large variety of olefinic compounds to form 1,2,3,4-tetrachloro-1,3-cyclohexadiene derivatives.Dehydrochlorination of these forms 1,2,4-trichloro aromatic compounds.Both double bonds in thiophene and N-methylpyrrole are annelated.Addition of tetrachlorothiophene dioxide to acyclic 1,5-dienes, which may contain a heteroatom, provides a facile synthesis of tetrachloroisotwistenes (51) and heteroisotwistenes (56) by a double Diels-Alder reaction.Acyclic 1,6-dienes lead to tetrachlorohomoisotwistene (59) and heterohomoisotwistenes (61).By use of 1,5-cyclooctadiene, sym-dibenzocyclooctatetraene, and 1,5-cyclononadiene, the more complex carbocycles 62, 65, and 66 are generated.Tetrabromothiophene dioxide reacts like the tetrachloro compound.